1. Field of the Invention
The present invention is to provide a method for forming a coating film on a facet of a semiconductor laser diode, in particular, the invention provides a method to enhance the ESD resistance of the laser diode.
2. Related Prior Art
It has been well known to coat the facet of the semiconductor laser diode (hereafter denoted as LD) by a combination of films of an aluminum oxide film, Al2O3, and a silicon oxide film, SiO2. It has been also well known that the LD is necessary to further enhance the electro-static discharge (hereafter denoted as ESD) resistance.
The present invention is to provide a method to form the LD with relatively higher ESD resistance.